Round to Flat slide conversion

[FATDADRACING]

I know enough about jetting to get me into trouble, so here's my situation. 79 YZ250 needs a carb which was a vm38 originally. Would the jetting be similar for the flat slide same size? What about performance issues? KISS says buy a direct replacement, but the prices are about the same.

[450exc115]

I would think if you called Sudco or Carb Parts Warehouse they would be able to match the jetting across both carbs and I would start there as a baseline.